1. Field of the Invention
This invention generally relates to microwave power sensors and, in particular, to such sensors which are constructed integrally with a monolithic circuit substrate.
2. Statement of the Prior Art
Various devices have been used for sensing microwave power. Such devices typically use one of a variety of sensors for converting microwave energy into heat and for responding to the resulting temperature change. Known devices include Wallaston wires, thermistors and thermocouples used in waveguides and coaxial transmission lines. Typically the sensing element is used as a microwave termination requiring that the microwave s characteristics of the sensing element be matched to the input transmission line. For this reason, the sensing elements must be designed to have a low VSWR within the waveguide or coaxial mounting and must also have a temperature dependent electrical characteristic. Because of these requirements, power sensors which are operable over very broad frequency bands have not previously been developed.
Also, as the use of microwaves in communications and surveillance increases so does the demand for performance at higher and higher microwave frequencies. This performance is inhibited in traditional circuit components by increases in the reactive impedance attributable to higher operating frequencies. As reactive impedance is proportional to component size, there is a constant need for research and development of smaller circuitry, components, and devices to enable higher frequency performance.